Recent advances in fluidic technology have led to the development of integrated chemical and biological analytical devices that place both electrical and fluidic systems on a single substrate. These devices sometimes are referred to as xe2x80x9claboratory-on-a-chipxe2x80x9d devices, and may offer advantages over the use of larger, traditional analytical devices. For example, integrated analytical devices may consume smaller quantities of reagents and/or solvents, may occupy a smaller footprint in a laboratory, and/or may be easier to adapt for use in the field.
Fully or partially integrated chemical and biological analytical systems typically include a microfluidic network for moving fluids through the system. The term xe2x80x9cmicrofluidicxe2x80x9d typically refers to systems and processes for moving fluids through very small channels, for example, with micron-scale diameters. A microfluidic network may include a wide variety of components, including, but not limited to, valves for controlling access to fluid channels, mixers for mixing reaction components and/or carrier fluids, and pumps for moving fluids through the network.
Various types of pumps are known for use in microfluidics systems. For example, some microfluidics systems utilize mechanical pumps that move fluids through the system via mechanically created pressure differentials. However, such pumping devices may be difficult to fabricate, and also may be damaged by impurities in the sample. Other microfluidics systems may utilize electroosmotic pumping devices, in which an electric field is used to drive a polar fluid through a channel. However, these systems may utilize a high voltage (on the order of kilovolts) to drive movement of the fluid, and may be sensitive to impurities that adsorb to the wall of the channel. Furthermore, electroosmotic pumping devices may not be able to pump effectively nonpolar or only slightly polar solvents.
Some embodiments of the present invention provide a microfluidic device including a fluidic pumping system. The fluidic pumping system includes a fluid-carrying channel, a plurality of acoustic pumping elements arranged along the fluid-carrying channel, wherein the acoustic pumping elements are configured to form an acoustic wave focused within the channel, and a controller in electrical communication with the plurality of acoustic pumping elements, the controller being configured to activate the acoustic pumping elements in such a manner as to cause the acoustic wave to move along the channel to move the fluid through the channel.